45,358 research outputs found

    A simple algorithm for decoding Reed-Solomon codes and its relation to the Welch-Berlekamp algorithm

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    A simple and natural Gao algorithm for decoding algebraic codes is described. Its relation to the Welch-Berlekamp and Euclidean algorithms is given.Comment: 7 pages. Submitted to IEEE Transactions on Information Theor

    Separable elements and splittings in Weyl groups of Type BB

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    Separable elements in Weyl groups are generalizations of the well-known class of separable permutations in symmetric groups. Gaetz and Gao showed that for any pair (X,Y)(X,Y) of subsets of the symmetric group Sn\mathfrak{S}_n, the multiplication map X×Y→SnX\times Y\rightarrow \mathfrak{S}_n is a splitting (i.e., a length-additive bijection) of Sn\mathfrak{S}_n if and only if XX is the generalized quotient of YY and YY is a principal lower order ideal in the right weak order generated by a separable element. They conjectured this result can be extended to all finite Weyl groups. In this paper, we classify all separable and minimal non-separable signed permutations in terms of forbidden patterns and confirm the conjecture of Gaetz and Gao for Weyl groups of type BB.Comment: 20 pages, 2 figures, comments welcom

    Comments on Unified dark energy and dark matter from a scalar field different from quintessence

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    In a recent paper by C. Gao, M. Kunz, A. Liddle and D. Parkinson [arXiv:0912.0949], the unification of dark matter and dark energy was explored within a theory containing a scalar field of non-Lagrangian type. This scalar field, different from the classic quintessence, can be obtained from the scalar field representation of an interacting two-fluid mixture described in the paper by L.P. Chimento and M. Forte [arXiv:0706.4142
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